Flexible-conduit cutting tool



-Oct.l13, 1953 F, v SCHLE|MER 2,654,941

FLEXIBLE-CONDUIT CUTTING TOL Filed Jan. 15, 1951 f lNvENTOR.

FLOV V SCHLE/MER ATTORNEY.

Patented Oct. 13, 1953 UNITED STATES PATENT OFFICE Claims.

My invention relates to cutting tools, and more particularly to a tool adapted for the cutting of flexible conduit.

Conventional practice in the cutting of flexible conduit entails the use of a hack saw which at best is inconvenient and conducive to mutilation of the conduit and such conductors as may be housed therein.

Attempts to depart from the aforementioned hack saw method have led to the development of various types of tools based on the principle of pliers, wherein a cutting jaw or jaws are relied on to slit the conduit transverse to the spiral turns of which the conduit vis formed.

Granted that such tools could be designed to slit such type of conduit, it requires no stretch of the imagination to appreciate the distortions and burrs which the use of such tools would cause, thus rendering the use of such conduit hazardous thereafter, in electrical installations.

Among the objects of my invention are:

(1) To provide a novel and improved tool for cutting exible conduit;

(2) To provide a novel and improved tool for cutting flexible conduit without introducing permanent distortion in the conduit or leaving burrs along the edges of the cut;

(3) To provide a novel and improved tool of simple but rugged design for cutting flexible conduit;

(4) To provide a novel land improved conduit cutting tool which will not bind or stall during a cutting operation;

(5) To provide a novel and improved conduit cutting tool which may be employed in cutting conduit which has already been installed and close to a wall surface.

(6) To provide a novel and improved conduit Acutting tool utilizing a circular sav and permitting a sensitive application of pressure thereto.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of the same,v taken in. conjunction with the accompanying drawings wherein- Figure 1 is a side elevational view of my invention in its preferred form and in open position;

Figure 2 is a view in section taken in the plane of the rotary saw of Figure 1 and with the device in condition for operation;

Figure 3 is an end view of the device in the condition of Figure 2;

Figure 4 is a plan view of the device in the condition of Figure 2;

Figure 5 is a view of a section of flexible conduit after severance by the device of my invention.

Referring to the drawings, my improved conduit cutting tool involves a rotary saw holder I which comprises an open-bottom casing 3 and lateral offset end extensions 5 and 1 integral therewith, the casing preferably being also open at one side and provided on its other side with a central bearing 9.

Within the casing is a rotary saw II of a diameter sufficient to expose a portion of its cutting periphery through the bottom of the casing. This saw is mounted on a shaft I3 which is journalled in the bearing 9 and which extends therebeyond for the application thereto of means such as a handle l 5 or suitable motor for rotation of the saw.

A cover plate I1 may be applied across the open side of the casing, following the installation of the saw therein.

Hingedly secured to the end extension l so as to lie beneath the casing in the plane of the rotary saw, is a cradle I9 for the reception and support of a conduit 2|. Such cradle is preferably formed of sheet metal and is so shaped as to provide a conduit supporting section 23 at its hinged end and a conduit covering section 25 at the opposite end, with sufficient spacing between the two sections to permit of the exposure of that portion 2l of the conduit which includes the desired location of severance, in addition to providing for loading of a conduit in the manner indicated in Figure 1.

The cradle being hinged to the end extension of the saw holder, any conduit resting therein may be urged into 4contact with the saw as the saw is rotated, to thereby sever two or more of the convolutions of which the exible conduit is formed.

With such type of iiexible conduit, the slitting of a pair of adjacent convolutions is sufficient to permit the conduit to be unthreaded into two parts at 'that point.

Flexible conduit of the character with which we are concerned, possesses a substantial amount of longitudinal resiliency. Because of this, there is a. tendency for the cable to stretch and contract during cutting, if the revolutions of the saw are not maintained uniform, which under manual operation is exceedingly diiiicult to realize.

Accordingly, to stabilize the conduit at the region of cutting, I punch out from the material of the cradle, one or more inwardly turned tabs 29, positioned to engage the conduit between convolutions and as close as practical, to the 3 convolutions being acted upon by the rotary saw. In this manner the drag of the saw upon the conduit cannot act beyond one or two convolutions of the conduit at most. As an aid in this connection, the free edge 3l of the cradle may 5 be formed on a spiral and turned inwardly to similarly engage a conduit. While such tabs are shown in the conduit covering section 25 only, similar tabs might be incorporated to advantage in the conduit supporting section 23. 10

Normal1y the cradle is biased to its loading position, that is in spaced relationship to the saw, by resilient compression means introduced-A between the cradle and the saw holder. In the specic embodiment of my invention illustrated, 15`

such resilient means constitutes: a spira-l spring 33 mounted over the end of a stud 35 aiiixed to the free end of the cradle,V the spring` inr turrt being of suilcient length to enter and` engagethe bottom of an opening 31 in the extension 5`. 20

The manner of utilizing the cutting tool, of my invention becomesv more or' less apparent from the above description. The conduit is placed in the cradle with the desired. point; of

severance disposed below the-rotary saw; and' as 25 the conduit is urgedl into engagementv with the saw, the saw is rotated andv gradually' cuts through a pair ofthe convolutions of theconduit; leaving a clean cut with no'burrs along the edges thereof. conduit is removed from the cradle andY unthreaded into two parts' as previously mentioned;

It is noted alsov that'the tool maybe; employed' in cutting conduit in itsinstalled position, even though such conduitk be'alii'xed to a wall surface. 35

The operationl merelyinvol'ves the preliminary step ofr slipping" the cradle onto the* conduit. in'- stead of laying the conduit into thecardle when cutting free conduit;

In effecting' al cutting operation; pressures` 40 employed are important. Excessive' pressure. of the saw against the conduit; in initiating: such operation isl apt to cause the' saw` teeth to' dig too deeply and jam. Onceoa'cuth'asbeen started,

howevenincreased pressure maybe' applied. I'ri- 45 asmuch as the pressure isappliedA manually, the degree of appliedl pressure is therefore under; the sensitive control oftheoperator:

Of important signiiic'ance in the. construction of the tool is tliefact that.. the` conduit is sup.- 50

ported with its longitudinal axis in theplane' o'fl the saw; Thus'the'sawvcuts strictly'in line with. the longitudinal' axis' of the" conduit;. as' distinguished from a cut on an'anglefwithsuch axis'.

From this it will become apparentthatany bend- 55 for, andwhile--Ihavef disclosed thesamein its 65 preferred form,A the device'l is subject, to' alteration and modication, without" departing from the underlying principles: thereof;,and"I, Aaccorde ingly, do not desireto be'limitedi'n my-protectin.

to the specific` detailsk illustrated; and=described 7()v except asma-y bevnecessitated by theappended claims.

I claim:

l. A ii'exibleeconduit cutter comprising,aro.

tary-saw holder',1a rotary saw supportedlthere.- 75,;

Following the cuttingyr operatiom the 30 by and having a portion of its cutting periphery exposed, means for rotating said rotary saw, and means for supporting a conduit against the exposed cutting periphery of said saw and with the longitudinal axis of said conduit in the plane of said saw, said means including a cradle havin-g a conduit supporting section at one end and a conduit covering section at its other end in longitudinal spaced relationship to said supporting sectionto permit of the loading of a conduit therein, and means hingedl'y securing said cradle at its conduit supporting end to said rotary saw holder with the plane of said rotary saw coinciding with the median longitudinal plane of the Cradle.

2;A` flexible-conduit cutter comprising, a rotary-saw holder including a casing, a rotary saw support-'ed'i'rr said casing and having a portion of itscutting periphery exposed, means for rotating sai'd rotary saw, a cradle for receiving and supportingv a conduit to. be cut,Y in adjustable proximity to: the exposed' cutting' periphery, of said' saw, said cradle including a conduit supporting sectionat one end and a conduit' covering se'ctionzat its` otheren'dlin' longitudinal spacedv relationship toM said' supporting`- section' to permit off the loading' of a conduit' thereinancl means for engaging's'uc'h conduit between convolutions on the saw engageable side of suoli' conduitforI stabilizing such conduitaga'ins't longitudinal flexing' along said saw' enga-geable side whenurged into` contact with' the' exposed peripheral' p'ortion' of said'. rotary' saw' while in m'otion sai'c'l means including' a' t'ab depending' from s'aid' conduit covering section of' said' cradle.

3. AY l'exble-conduitA cutter" comprising; a rotary-saw` holder" including' a casing, a rotary saw journalled in' said' casing' and' having a portion of its' cutting periphery ex'p''sed; means for rotatingj saidro'tary saw, a' cr'a'dle'fo'r' receiving and supporting' a conduit' to' be c'utg, with.. aV portion of such. conduitV exposed which' includes the desired" location of'K severance, meansl hingedly securing said cradle to saidfrotarylsaw holder with saidcra'dlein p'roximitytoitlie' exposed portionof the cutting periphery' of said's'a'w; and resilientA compression means interposed. between said rotary-saw' holder and said cradle' to normally maintain separation' o'f` said' cradle andsaid saw in theabsen'c'e of an`oppo'sing pressure exceeding that offered by said resilient,compression-means.

4: A' nexibie-condiut cutter comprising, a rotary-'saw holderincl'udin'g'aA ca's'i'ng', arotary saw journalled in said Vcasing and' having a portion ofl it'sCUttingp'eriphery exp'o'se'm'e'ans for rotating'saidrotarysaw; a cradleior 'receiving and supporting a'vv conduit to' be' c'ut, said' cradle havinga conduit supporting section' at' one end-and a conduit covering section at" the' other' endwith sufficient' spacing between the' twosections to permit of` theloa'ding of a conduittherein, lmeans hingedly securing said cradle'at it's conduit supporting: end to saidrotaryisaw'holder' and with saidcradle'in' proximity to' the'exposed portion of the'cutting' periphery of' said saw, resilient compression means interposed between said rothat offredby' said'resilient-compressionmeans,-= and" mea'ns' for stabilizing'.- suchA conduitfinsaid` cradle duringv sawing thereof.

5. A' iiexible-conduit cutter comprising, a rotary-saw holder including alcasing', a rotary'saw.

journalled in said casing andfhaving: afpcrtion of its cutting periphery exposed, means for rotating said rotary saw, a cradle for receiving and supporting a conduit to be cut, said cradle having Ia conduit supporting section at one end and a conduit covering section at the other end with sufficient spacing between the two sections to permit of the loading of a conduit therein with the desired location of severance exposed, means hingedly securing said cradle at its conduit supporting end to said rotary-saw holder and With said cradle spacing in proximity to the exposed portion of the cutting periphery of said saw, resilient compression means interposed between said rotary-saw holder and said cradle to normally maintain separation of said cradle and 1 said saw in the absence of an opposing pressure exceeding that offered by said resilient compres- 6 sion means, and means for stabilizing such conduit when introduced into said cradle, to hold such conduit against substantial lateral movement when urged into contact with the exposed peripheral portion of said rotary saw while in motion.

FLOYD V. SCHLEIMER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,031,470 Eck et al Feb. 18, 1936 2,374,753 Kramer May 1, 1945 2,396,442 Shaner et al Mar. 12, 1946 5 2,502,656 Koen Apr. 4, 195o 

